Radiant energy generating and distributing apparatus



April 1965 J. A. GIALANELLA 3,179,789

RADIANT ENERGY GENERATING AND DISTRIBUTING APPARATUS Original Filed Feb.8. 1960 INVENTOR r/aser-w fl- G'MAAA/HLA? ATTORNEY United States Patent3,179,789 RADHANT ENERGY GENERATING AND DESTRHBUTKNG APPARATUS Joseph A.Gialanelia, 28 Cypress Ave, North (Ialdweil, NJ. Continuation ofapplication Ser. No. 7,3ti7, Feb. 8, 1950. This application Aug. 26,1963, Ser. No. 365930 2 Claims. (Cl. 219-349) The present inventionpertains to improvements in radiant energy generating and distributingapparatus. This application is a continuation of my copending UnitedStates application Ser. No. 7,307, filed February 8, 1960.

The use of radiant energy in a wide range of modern processes, typicallyheating and drying by means of infrared rays, has been hampered in manycases by such disadvantages as relatively low efiiciency of the energygenerator in the transfer of energy to a target area or operating zone,difliculty of obtaining uniform heat application, high cost, and lack ofready adaptability to special requirements.

With a view to eliminating these and related prior ditficulties, oneobject of the present invention resides in the provision of means forproducing radiant energy at maximum efiiciency in selected spectralzones such as the infrared, though not limited thereto.

Another object is to provide apparatus of the above type which may besimply and readily manufactured at low cost.

A further object resides in the provision of apparatus of the above typeincluding an exterior main reflector cooperative with the energy source,an uncoated segmental zone of the tubular envelope being directed towardthe reflector.

Another object is to provide a device of the above nature in which thecontrol coatings may have a high absorptive characteristic, or a highabsorptive coating and a high reflective coating superimposed thereon.

A further object is to provide heating apparatus in which controlcoatings may be selectively applied both to the source envelope and themain reflector, to attain any desired distribution or concentration ofthe generated radiation.

Other objects and advantages of the invention will become evident duringthe course of the following description in connection with theaccompanying drawings, in which FEGURE l is a perspective view of apreferred form of generating unit;

FIGURE 2 is a front view of the generator tube and main reflectorassembly;

FIGURE 3 is a typical cross section illustrating the relation of thecoated generator tube to the main reflector; and

FEGURE 4 is an enlarged diagrammatic cross section of a typicalgenerator envelope illustrating the use of a segmental coating of highabsorptive value backed by a coating of high reflectivity.

In the use of elongated generators for radiant energy, such as infrared,it is customary to employ a concave redoctor to gather and direct thegenerated rays to the desired zone of application. However, thereflector obviously can control and direct only such rays as fall uponits directing surface, while the primary energy source or filament emitsrays in all directions. Asa result, with the usual tubular generator alarge proportion of the rays emitted from the convex side of the tubefacing outward never reach the reflector, but instead merely escapedivergently and are lost from the operating zone. It has been found thatthe capture of the divergent rays and thier retention within the usefulprocess region will greatly improve operational efiiciency of theapparatus.

Referring now to FIGURE 1, the numeral 15 denotes a tubular sheath orenvelope, preferably of fused silica opaque to light. Silica opaque tolight is preferred at the present time because of its lower costcompared to transparent quartz. The word opaque as customarily appliedto this material refers to its milky appearance in contrast to clearquartz or the like, but in fact it possesses a high degree oftransparency for infrared rays in the range up to 4 microns. Enclosedwithin the envelope 15 is a filament to of high resistance wire, woundin an elongated helix and provided with terminal electrodes It?extending through and supported by end caps 18. A substantiallysemi-cylindrical zone of the tube 15 is covered by a coating 19 (FIG. 3)or by coatings 21 and 22 (FIG. 4) which in the instant embodimentextends throughout the active length of the tube.

Under normal operating conditions, the generator unit is mounted in anelongated trough-like reflector 20, FIG- URES 2 and 3, the terminalelectrodes being held in receptacles 13 of any suitable type as forinstance spring loaded connectors, permitting insertion and removal ofthe generator unit through the end of reflector assembly.

, Referring to FIGURE 3, it will be noted that the tube 15 is mountedclosely adjacent to the inner curve of the reflector, and that the sideof the tube carrying the coating 19 is orientated outward, that is inthe direction away from the reflector 26.

The coating 19 may be of any highly absorptive mate rial, by forming itof a black body material as carbon, molybdenum disulfide, aluminumoxide, etc. As an alternative, a composite coating may be usedconsisting of an inner absorptive layer 21 on which is superimposed areflective layer 22 as shown in FIGURE 4. It will be understood thatFIGURE 4 is diagrammatic in crosssection in the sense that for purposesof clarity the thickness of the coatings has necessarily beenexaggerated.

In the case of the absorptive coating, improved results are attained byreason of the high black body emissivity characteristic of the chosenmaterial. Here again the arcuate coating intercepts all direct raysthrough the front of the tube and absorbs the greatest part of them,raising its surface to a relatively high temperature. Since all suchsurfaces radiate in proportion to their emissivity and their absolutetemperature, the coating surface emits a large proportion of itsabsorbed heat inwardly and outwardly from the inner and outer surfacesof the coating respectively, again conserving radiation and agumentingthe total radiation by fact of the black body radiation from increasedsurface area.

In the arrangement shown in FIGURE 4 the inner absorptive layer 21 actsin the same manner as just described, while the outer reflecting layer22 receives any heat tending to emanate from the outer surface of thelayer and returns the major portion of it to the latter forreabsorption, thus preventing undue loss from convection and conduction,with the result that high temperatures and consequent improved operativeefiiciencies are obtained.

While in practice the choice among the two arrangements decribed is madein accordance with various factors of intended use such as area ofapplication, spacing of the generating apparatus from the work, etc., itwill be noted that all operate in the same basic control manner toconserve radiant energy and increase the intensity and efficiency of itsgenerated output.

With regard to the envelope 15 in all examples, the desired surfaceportion intended to receive an absorptive coating may be etched, thusproducing a roughened inner surface of the applied coating withconsequent maximum absorptive and radiating characteristics.

As previously mentioned, the opaque fused silica envelope 15 has theadvantage of high transparency in the desired spectral region. Otheradvantages are strength, the

ability to withstand high temperature, and low cost in comparison tomaterials such as clear quartz. This low cost, coupled with the factthat the envelope 15 is a simple tube of homogeneous structure,obviously promotes economical manufacture. Other factors of economy areelimination of reflectors and the like Within the tube, and the ease ofapplying the requisite control coatings to the outer tube surface.

The foregoing description or the invention has been directed mainly to atypical field of advantageous application, namely that of infra-red, butit will be obvious that its basic structures and mode of operation cansimilarly be employed in connection with other visible and invisiblewavelength ranges. Thus when required, gaseous discharge may besubstituted for heated filaments, various pigments may be applied to theinterstices between sectional coatings of selected forms, and similardetail measures taken to meet particular conditions. In other Words,while the invention has been set forth in preferred form, it is notlimited to the precise examples illustrated, as various modificationsmay be made without departing from the scope of the appended claims.

What is claimed is:

1. In an apparatus for generating and distributing radiant energy, incombination, an elongated source of infrared rays, a tubular envelopeenclosing said source and transparent to said rays, an elongated mainreflector directed toward said source to receive radiant rays from saidsource and re-direct said rays in a path in which said source islocated, a relatively highly absorptive coating means on an outwardlydirected arcuate portion of said envelope presenting an arcuate interiorsurface facing said reflector to increase the radiant surface of saidapparatus and to cooperate with said main reflector in increasing thetemperature of said source and envelope as Well as to provide maximumtemperature of said coating to thereby minimize the development ofconvection heat and augment the infrared radiant energy produced by saidapparatus.

2. Apparatus as set forth in claim 1 and including a reflective coatingsuperimposed on the exterior outwardly directed surface of saidabsorptive coating.

References Cited by the Examiner UNITED STATES PATENTS 606,792 7/98Quida's 219-342 1,110,532 9/14 Byce 338218 X 1,686,865 10/28 Klotz219349 1,822,076 9/31 Bauersfeld et a].

1,954,128 4/34 Heyroth et al 219461 2,152,934 4/39 Trent 219-5402,658,984 11/53 Mohn 219354 3,015,711 1/62 Bridwell 2l9531 FOREIGNPATENTS 160,486 3/21 reat Britain.

382,099 9/23 Germany.

445,532 4/36 Great Britain.

519,137 3/40 Great Britain.

RICHARD M. WOOD, Primary Examiner.

1. IN AN APPARATUS FOR GENERATING AND DISTRIBUTING RADIANT ENERGY, INCOMBINATION, AN ELONGATED SOURCE OF INFRARED RAYS, A TUBULAR ENVELOPEENCLOSING SAID SOURCE AND TRANSPARENT TO SAID RAYS, AN ELONGATED MAINREFLECTOR DIRECTED TOWARD SAID SOURCE TO RECEIVE RADIANT RAYS FROM SAIDSOURCE AND RE-DIRECT SAID RAYS IN A PATH IN WHICH SAID SOURCE ISLOCATED, A RELATIVELY HIGHLY ABSORPTIVE COATING MEANS ON AN OUTWARDLYDIRECTED ARCUATE PORTION OF SAID ENVELOPE PRESENTING AN ARCUATE INTERIORSURFACE FACING SAID REFLECTOR TO INCREASE THE RADIANT SURFACE OF SAIDAPPARATUS AND TO COOPERATE WITH SAID MAIN REFLECTOR IN INCREASING THETEMPERATURE OF SAID SOURCE AND ENVELOPE AS WELL AS TO PROVIDE MAXIMUMTEMPERATURE OF SAID COATING TO THEREBY MINIMIZE THE DEVELOPMENT OFCONVECTION HEAT AND AUGMENT THE INFRARED RADIANT ENERGY PRODUCED BY SAIDAPPARATUS.